Our results suggest the type of green space does matter. Adults with 30% or more of their neighbourhood covered in some form of tree canopy had 31% lower odds of developing psychological distress. The same amount of tree cover was linked to 33% lower odds of developing fair to poor general health.

We also found poorer mental and general health among adults in areas with higher percentages of bare grass nearby, but there’s likely more to that than meets the eye.

How did we do the research?

Our research involved tracking changes in health over an average of about six years, for around 46,000 adults aged 45 years or older, living in Sydney, Newcastle or Wollongong. We examined health in relation to different types of green space available within a 1.6 kilometre (1 mile) walk from home.

Our method helped to guard against competing explanations for our results, such as differences in income, education, relationship status, sex, and age. We also restricted the sample to adults who did not move home, because it is plausible that people who are already healthier (for instance because they are more physically active) move into areas with more green space.

So is the answer simply more trees and less grass? Not exactly. Let’s get into the weeds.

Trees make it cool to walk

Imagine you’re walking down a typical street on a summer’s day in the middle of an Australian city. It’s full of right angles, grey or dark hard surfaces, glass structures, and innumerable advertisements competing for your attention. Then you turn a corner and your gaze is drawn upwards to a majestic tree canopy exploding with a vivid array of greens for as far as you can see.

A tree-lined street like Swanston Street in Melbourne is a more walkable street.kittis/Shutterstock

Let’s get the obvious out of the way. Walking down this green street, you may instantly feel some relief from the summer heat.

Feeling restored and alert

But as the minutes of walking beneath this natural umbrella of lush foliage accumulate, other things are happening too. The vibrant colours, natural shapes and textures, fresh aromas, and rustling of leaves in the breeze all provide you with effortless distraction and relief from whatever it was you might have been thinking about, or even stressing over.

Friends, old and new

You walk past groups of people on the footpath taking time to catch up over coffee in the shade. Some research has found that tree cover, rather than green space more generally, is a predictor of social capital. Social capital, according to Robert Putnam, refers to the “social networks and the associated norms of reciprocity and trustworthiness” that may have important influences on our life chances and health.

You walk further and a chorus of birdsong soars through the neighbourhood noise. Trees provide shelter and food for a variety of animals. Research suggests tree canopy tends to be more biodiverse than low-lying vegetation.

Green spaces with tree canopy are settings where communities can come together to watch birds and other animals, which can also be catalysts for new conversations and developing feelings of community belonging in the neighbourhoods where we live … just ask dog owners.

Parks with a variety of vegetation, including trees and grass, may be more attractive for a wider range of outdoor activities than those with few trees.Author

Furthermore, large areas of bare grass in cities can make built environments more spread-out and less dense. Without tree canopy to shield from the midday sun, this may increase the likelihood of people using cars for short trips instead of walking through a park or along a footpath. The result is missed opportunities for physical activity, mental restoration, and impromptu chats with neighbours. Previous work in the United States suggests this might be why higher death rates were found in greener American cities.

Grassed areas can occupy a large amount of space for surprisingly little mental health benefit.chuttersnap/Unsplash

Large open areas of grass can be awesome for physical activity and sport, but let’s make sure there is also plenty of tree canopy too, while also thinking about ways to get more people outdoors in green spaces. Here are some suggestions.

Making Australia greener and healthier

As the density of Australian cities continues to increase and more of us live in apartments and/or work in high-rise office blocks, it is great to see strategies to invest in tree cover and urban greening more generally across Australia. Cities with such plans include Sydney, Melbourne, Brisbane, Bendigo, Fremantle, and Wollongong.

Today Americans live in a world that thrives on being busy, productive and overscheduled. Further, they have developed the technological means to be constantly connected to others and to vast options for information and entertainment through social media. For many, smartphones demand their attention day and night with constant notifications.

As a result, naturally occurring periods of solitude and silence that were once commonplace have been squeezed out of their lives. Music, reality TV shows, YouTube, video games, tweeting and texting are displacing quiet and solitary spaces. Silence and solitude are increasingly viewed as “dead” or “unproductive” time, and being alone makes many Americans uncomfortable and anxious.

We study and teach outdoor education and related fields at several colleges and organizations in North Carolina, through and with other scholars at 2nd Nature TREC, LLC, a training, research, education and consulting firm. We became interested in the broader implications of alone time after studying intentionally designed solitude experiences during wilderness programs, such as those run by Outward Bound. Our findings reveal that time alone in nature is beneficial for many participants in a variety of ways, and is something they wish they had more of in their daily life.

Reflection and challenge

We have conducted research for almost two decades on Outward Bound and undergraduate wilderness programs at Montreat College in North Carolina and Wheaton College in Illinois. For each program, we studied participants’ experiences using multiple methods, including written surveys, focus group interviews, one-on-one interviews and field notes. In some cases, we asked subjects years later to look back and reflect on how the programs had affected them. Among other questions, our research looked at participant perceptions of the value of solo time outdoors.

Our studies showed that people who took part in these programs benefited both from the outdoor settings and from the experience of being alone. These findings build on previous research that has clearly demonstrated the value of spending time in nature.

Scholars in fields including wilderness therapy and environmental psychology have shown that time outdoors benefits our lives in many ways. It has a therapeutic effect, relieves stress and restores attention. Alone time in nature can have a calming effect on the mind because it occurs in beautiful, natural and inspirational settings.

Spending time in city parks like Audubon Park in New Orleans provides some of the same benefits as time in wilderness areas, including reduced stress levels and increased energy levels.InSapphoWeTrust, CC BY-SA

Nature also provides challenges that spur individuals to creative problem-solving and increased self-confidence. For example, some find that being alone in the outdoors, particularly at night, is a challenging situation. Mental, physical and emotional challenges in moderation encourage personal growth that is manifested in an increased comfort with one’s self in the absence of others.

Being alone also can have great value. It can allow issues to surface that people spend energy holding at bay, and offer an opportunity to clarify thoughts, hopes, dreams and desires. It provides time and space for people to step back, evaluate their lives and learn from their experiences. Spending time this way prepares them to re-engage with their community relationships and full work schedules.

Putting it together: The outdoor solo

Participants in programmed wilderness expeditions often experience a component known as “Solo,” a time of intentional solitude lasting approximately 24-72 hours. Extensive research has been conducted on solitude in the outdoors because many wilderness education programs have embraced the educational value of solitude and silence.

Solo often emerges as one of the most significant parts of wilderness programs, for a variety of reasons. Alone time creates a contrasting experience to normal living that enriches people mentally, physically and emotionally. As they examine themselves in relation to nature, others, and in some cases, God, people become more attuned to the important matters in their lives and in the world of which they are part.

Solo, an integral part of Outward Bound wilderness trips, can last from a few hours to 72 hours. The experience is designed to give participants an opportunity to reflect on their own thoughts and critically analyze their actions and decisions.

For some participants, time alone outdoors provides opportunity to consider the spiritual and/or religious dimension of life. Reflective time, especially in nature, often enhances spiritual awareness and makes people feel closer to God. Further, it encourages their increased faith and trust in God. This often occurs through providing ample opportunities for prayer, meditation, fasting, Scripture-reading, journaling and reflection time.

Retreating to lead

As Thomas Carlyle has written, “In (solitary) silence, great things fashion themselves together.” Whether these escapes are called alone time, solitude or Solo, it seems clear that humans experience many benefits when they retreat from the “rat race” to a place apart and gather their thoughts in quietness.

In order to live and lead effectively, it is important to be intentional about taking the time for solitary reflection. Otherwise, gaps in schedules will always fill up, and even people with the best intentions may never fully realize the life-giving value of being alone.